Mixing Enhancement of Non-Newtonian Fluids Using Unconventional Configurations

Dynamic perturbations and off-centered single impeller configurations have been investigated to reduce mixing time with shear thinning fluids. The use of a color-decolorization technique based on a fast acid-base reaction allowed to measure mixing times and to reveal the presence of both segregated and dead zones. A statistical design approach has been used to evaluate the effect of the impeller position as well as the dynamic conditions and their interactions. Mixing times and flow patterns for shear thinning fluids were presented and compared to conventional operating modes. Homogenization was significantly enhanced when a radial flow impeller was used under both off-centered and dynamic perturbation conditions. In the case of an axial flow impeller, a combination of a large axial displacement with long clockwise times and short counter-clockwise times gave better mixing times.